However, there's a bit of confusion:
* There is no film with that exact title released in 1931.
* There are a few films that might be what you're thinking of.
Here are a few possibilities and their casts:
1. "La Scala - Love's Melody" (1931): This film is actually a different movie from the one you mentioned. It was produced by Fox Film Corporation, and starred Lawrence Tibbett, Helen Chandler, and Frank Morgan. This musical film was a huge success, and it's likely the one you're thinking of.
2. "La Scala" (1938): This film stars Luigi Zoja and Assia Noris. This Italian film tells the story of a young man who falls in love with a woman who is engaged to a famous tenor.
3. "La Scala" (1959): This film stars Robert Alda and Anna Maria Ferrero. It's a French-Italian film that centers around a young opera singer who gets caught up in a scandal.
To help you find the specific movie you are looking for, please provide more details:
* What is the plot of the film you are thinking of?
* Are there any specific actors or actresses that you remember?
* Do you remember any scenes or specific details from the film?
With more information, I can help you identify the correct film and provide you with the full cast list.